The Statistical Coordinating Center's (SCC) primary functions are to support the collection and analysis of data for the Breast Cancer Surveillance Consortium, develop and implement new statistical methodology that will characterize the process of mammography, and provide scientific guidance in the development of publications. The major goals of the Consortium are to provide population-based information on the performance of breast cancer screening in the community, improve the process of tumor detection, examine the role of practice patterns and biological factors on outcomes, and evaluate the efficacy of mammography in reducing breast cancer morbidity and mortality. In the last four years the SCC has established a standardized data collection system, constructed standardized questions, analyzed 1.5 million mammograms for inclusion in three papers underway, and assessed reader variability in interpretation of mammograms. In the next five years, the SCC will do the following: (1) Implement methods that continue to improve comparability of data across sites by improving quality control and maintaining standardized data collection instruments; (2) Maintain a data management system that facilitates pooled analyses and rapid development of new projects; (3) Conduct analyses of the outcomes of screening and symptomatic mammography to identify predictors and sources of variation across sites; (4) Develop statistical methods that allow for modeling of hierarchical, longitudinal data with covariates at the site, radiologist, or woman level; (5) Develop methods to evaluate the efficacy of the BIRADS 0 (incomplete) on outcomes; (6) Evaluate accuracy in a population undergoing repeat mammography; and (7) Provide scientific leadership and dissemination by maintaining a Consortium Web page, conducting annual meetings of the Data Managers and Statisticians, conducting site visits, and participating in the scientific leadership by developing proposals, conducting analyses, and publishing the results.